The present invention relates to an indicating device for indicating an unauthorized opening of a door of an aircraft parked on the ground, as well as to a door arrangement and an aircraft comprising such an indicating device.
For reasons of safety and security all externally accessible doors of an aircraft parked on the ground are sealed with adhesive security seals prior to leaving the aircraft behind unattended. The security seals are designed and used such that the doors cannot be opened without destroying or at least irreversibly damaging the security seals, so that a missing or damaged security seal indicates that in the absence of authorized persons, non-authorized access to the aircraft has occurred or has been attempted. In such an instance, the typical safety or security precautions require a complete inspection of the aircraft, that is, the entire aircraft must be searched by security personnel for possible intruders and dangerous objects.
The security seals are complex and time-consuming with regard to application since they have to be manually applied, checked and removed without residue by a person. Moreover, their use is associated with false alarms since they are susceptible to moisture and dirt and may drop off, and since they may also be damaged due to relative thermal expansion between a door and an aircraft fuselage without an unauthorized opening of the door. Moreover, security seals may be forged or may come into possession of unauthorized persons, and have to be re-purchased continuously since they are meant to be used only once.